Snakebite is not uncommon in many parts of the world, predominantly in the tropical areas. Snakes of pit vipers (Crotalidae) and vipers (Viperidae) have pronounced tissue damage effect on envenomation. In many cases, such histolysis is not prevented by the use of antivenin unless it is administered immediately. Our immediate goal is to determine the chemical properties of the toxins responsible for hemorrhage and necrosis and ultrastructural mechanism of tissue damage on envenomation. Snake venoms will be fractionated and the fractions responsible for myonecrosis, hemorrhage, and renal necrosis will be investigated for their chemical and pathologic properties. We hope that our research will contribute to the long-range objective of better snakebite treatment, especially for the prevention of tissue damage.